Patent Document 1 discloses an impact tool which strikes a tip tool using pressure in a pressure chamber. The impact tool disclosed in Patent Document 1 includes: a cylindrical cylinder provided in a casing; a piston reciprocally housed in the cylinder; a tip tool held by the cylinder; a striking element reciprocally provided in the cylinder; an intermediate striking element disposed between the tip tool and the striking element in the cylinder; and an air chamber formed between the piston and the striking element in the cylinder. A respiration hole communicating with the air chamber is formed on the cylinder. Provided in the casing are a motor, and a power conversion mechanism for converting a torque by an output shaft of the motor into a reciprocating force for the piston.
In the impact tool disclosed in Patent Document 1, the torque by the output shaft of the motor is converted into the reciprocating force of the piston. When the piston moves in a direction separated from the striking element, the pressure in the air chamber decreases. In contrast to this, when the piston moves in a direction approaching the striking element, the pressure in the air chamber increases to apply a striking force to the tip tool through the intermediate striking element.